Burglarproof door lock



y 4, 1940. E. l. BROWN 2.200.834

BURGLARPROOF DOOR LOCK I Filed June 6, 1938 I 2 Sheets-Sheet 1 attorneg 3m entor I y 4, 1940. E. 1. BROWN BURGLARPROOF DOOR LOCK Filed June 6, 1938 2 Sheets-Sheet 2 Z Fig. 1

Fi i ZZ INVENTOR. BY Edward 5/060/7.

ATTORNEY Patented May 14, 1940 UNITED STATES PATENT OFFICE 2,200,834 BUR-GLARPROOF DOOR LOCK Application June 6, 1938, Serial No. 212,172

2 Claims.

This invention relates to what are termed burglarproof door locks, or safety locks, which cannot be picked from outside the door, or opened in any way without a proper key, and such locks cannot be opened with a key from the outside of the door when the locking pin or knob is used on the inside of the door.

The object of this invention is the production of a lock of the character described, having parts of special construction and arrangement whereby it is believed a particularly safe, durable and protective lock is designed, of simple mechanism, readily and cheaply manufactured and easily assembled, and which cannot get out of order in regular use.

In the accompanying drawings forming a part of this application the construction and combinations of the various parts are illustrated.

Fig. I is a front view of a portion of a door with this invention applied.

Fig. II is an edge view of the door portion with this invention in place in the door.

Fig. III is an interior view of the lock casing showing all parts assembled therein and in their relative positions.

Fig, IV represents a sectional view taken along the line IV-IV of Fig. III.

Fig. V is an inside view of one end of the lock casing showing the elbow arm in its displaced position.

F'ig. VI is a sectional view taken along the line VI-VI of Fig. V.

Fig. VII is a plan view of the revoluble cam.

Fig. VIII is a side view of the revoluble cam.

Fig. IX represents a sectional view taken along the indirect line IX-IX of Fig. III.

Fig. X is a horizontal sectional view taken along the line X-X of Fig. III.

Throughout the drawings and description the same number is used to refer to the same parts.

The door i has inserted therein the lock casing 2 of any chosen pattern and structure. On the front and back of the door are the customary escutcheon plates 3 and 4. The door knob 5 has the ordinary shank 6 and is provided with the common spindle of square cross section fitting the orifice 6' in the rollback 1. The rollback is thus carried and rotated by the knob spindle. Adjacent the rollback I, as best shown in Fig. III, is the vertical portion 8 of a right angle elbow arm, the other portion 9 of the arm being provided with a head Ill through which is passed a pivot pin I! into the butt l2 of a unitary locking and latch bolt l3, the end of which is marked [4 and is shownprojecting from the lock casing. A lug I5 is extended from the inner surface of one side of the casing and passes transversely through the boltin rear of a coil spring l6 located in a longitudinal bore I! in the bolt. The bolt is thus spring projected into the position illustrated in Fig. III which may be termed the locking and latching position. To retain the spring and bolt associated as shown in the figure, a retaining screw I8 is introduced in the bore of the bolt on the other side of lug I5 from the spring.

As best shown in Fig. X, therewill be noted a screw l9 which secures one end of the flat spring iii! to a node of the interior of the casing, and the free end of the spring is placed in contact with a projection 2| with which the portion 9 of the elbow is provided. Normally, therefore, the spring presses the part 9 of the elbow into the position set out in the figure.

Considering Figs. III and IV, there will be observed a circular cam 22, supported rotatably within the casing by the three spaced rollers 23, 24, 25. As also. illustrated in Fig. VIII the cam has a curved portion 26 which increases in thickness from the point thereof. A keyhole 21 is formed in the hub or center 28 of the cam, and the cam may be revolved by a key inserted in the keyhole 21.

In Figs. V, VI and VII there will be seen the pin 30 and the pinhole 3| through the cam near its periphery. The casing is also provided with a like pinhole 3| as indicated in Fig. 6, and When the cam is suitably revolved the pinholes in the cam and casing register and the pin 30 may be introduced into the cam pinhole 3|. The cam is thus held in a static-nary position. It will be understood that the pin 30 is located upon the-inside of the door l.

The hub 28 of the cam may extend through a circular face plate 29 on the escutcheon plate 3. This invention is not intended to be limited to that construction and arrangement, or to the precise shapes or relative sizes of the elements shown. In the Figs. III and IX are shown the headed hardenedsteel pins 32 and 33 inserted in the end of the bolt marked l4 so that the end cannot be sawed off. There will be observed also in Figs.

VI and X a lug 34 on the inner surface of the removable back of the casing. The lug is arranged in the path of the vertical portion 8 of the elbow 9 and prevents the inward movement of the bolt l3, unless the parts are cam operated into the positions set out in Fig. X.

The operation of this invention will be followed by the inspection of Figs. III, IV and V. Normally, the flat spring presses the elbow into posiagainst the projection of the elbow mentioned,

tion wherein one part of the elbow lies next to the rollback and when the rollback is turned by the knob, the elbow and bolt are reciprocated. But, as may be observed in Fig. IV, if the cam be rotated and the thicker part thereof brought ing, a spring projected locking and latching bolt. arranged to be moved outwardly and inwardly in I the. casing, an elbow arm pivotally attached to p the bolt and arranged tobe turned sidewise, a

door knob spindle having a rollback thereon arranged to act on said elbow arm to retract the bolt, a spring having one end attached to the casing. and, the other end arranged to press against the elbow arm to hold the arm in unlocking position, a circular cam, a plurality of spaced rollers arranged to carry the cam. rotatively in the casing,'said cam having a peripheral arcuate portion constructed with a thin part increasing to a thicker part, said cam portion adapted when rotated to act against the force of said spring and move the said elbow sidewise into locking position, means carried by the casing in the path of said elbow arm when said arm is in its locking position whereby the retraction of the said arm To open the.-

and the bolt is prevented, the back of said casing having an aperture, a pin insertable therein, said cam having a pinhole to receive the pin and hold the cam against rotation.

2. A door lock having in combination, a casing,

a spring projected locking and latching bolt arranged to be moved outwardly and inwardly with respect to the casing, an elbow arm pivotally attached to the bolt and arranged to ,be moved sidewise, a door knob having a spindle passing through the casing and having a rollback thereon arranged to act on said elbow arm to retract said bolt, a spring having one end attached to the casing and it's. remaining end arranged to press against said elbow arm to hold the arm in unlocking position, ,a. cam sup-ported rotatively in the casing and having a portion passing through the wall of the casing and constructed to receive a key, said cam having a peripheral arcuate portion constructed with a thin part increasing gradually into a thicker part, said elbow arm having a projection arranged in contact with said spring, said arcuate portion being constructed and ar-'- ranged to act upon said projection against the force of said spring to move said elbow arm side.- wise into locking position, a lug carried by the casing in the path of said. arm whereby the re.- traotion of said arm and bolt is prevented, when said armis. in its. locking position, a movable member adapted to be hand operated on the back of the casing and introduced into the casing, the back of the casing having an opening for the passage of said member into the casing, and said cam being provided with means, for engaging the inserted member whereby the rotation of. the cam is prevented,

EDWARD I. BROWN. 

